diff --git a/include/mbedtls/ecp.h b/include/mbedtls/ecp.h
index 76aef32fbc..3d14f36b31 100644
--- a/include/mbedtls/ecp.h
+++ b/include/mbedtls/ecp.h
@@ -1339,8 +1339,6 @@ int mbedtls_ecp_read_key(mbedtls_ecp_group_id grp_id, mbedtls_ecp_keypair *key,
  * \return          \c 0 on success.
  * \return          #MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL if the \p key
                     representation is larger than the available space in \p buf.
- * \return          #MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE if the operation for
- *                  the group is not implemented.
  * \return          Another negative error code on different kinds of failure.
  */
 int mbedtls_ecp_write_key(mbedtls_ecp_keypair *key,
diff --git a/library/ecp.c b/library/ecp.c
index 758d54bd76..66b3dc1be1 100644
--- a/library/ecp.c
+++ b/library/ecp.c
@@ -3305,7 +3305,7 @@ cleanup:
 int mbedtls_ecp_write_key(mbedtls_ecp_keypair *key,
                           unsigned char *buf, size_t buflen)
 {
-    int ret = MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
 
 #if defined(MBEDTLS_ECP_MONTGOMERY_ENABLED)
     if (mbedtls_ecp_get_type(&key->grp) == MBEDTLS_ECP_TYPE_MONTGOMERY) {